Giving a default object to my class method in PHP - php

Question

I want to pass a DateTimeZone object to my method in my class Test. I have the following code:
class Test {
function __construct( $timezone_object = new DateTimeZone() ) {
// Do something with the object passed in my function here
}
}
Unfortunately, the above doesn't work. It gave me an error. I know I can do the following instead:
class Test {
function __construct( $timezone_object = NULL ) {
if ( $timezone_object == NULL)
$to_be_processed = new DateTimeZone(); // Do something with my variable here
else
$to_be_processed = new DateTimeZone( $timezone_object ); // Do something with the variable here if this one is executed, note that $timezone_object has to be the supported timezone format provided in PHP Manual
}
}
However, I think that the second choice seems rather unclean. Is there a way to declare my method like the first choice?

Answer 1

If you're just looking for succinct code, you could do
class Test {
function __construct( \DateTimeZone $timezone_object = null ) {
$this->ts = $timezone_object ?? new DateTimeZone();
}
}
the double ?? is an if null check. So you have the type hinting which will only allow DateTimeZone or Null value in (so that's safe), then you just assign a new DateTimeZone instance if the argument was null, otherwise, use the passed in value.
Edit: Found info on default null for PHP 7.1+
Cannot pass null argument when using type hinting
So the code could be even more esoteric, with slightly less key strokes
class Test {
function __construct( ?\DateTimeZone $timezone_object ) {
$this->ts = $timezone_object ?? new DateTimeZone();
}
}
But in my opinion, this is just horrible.